<html><head><base href="placeholder"></head><body><div class='definition'><pre>java.lang<br>public final class <b>String</b>
extends <a href="psi_element://java.lang.Object"><code>Object</code></a>
implements <a href="psi_element://java.io.Serializable"><code>java.io.Serializable</code></a>,&nbsp;<a href="psi_element://java.lang.Comparable"><code>Comparable</code></a>&lt;<a href="psi_element://java.lang.String"><code>String</code></a>&gt;,&nbsp;<a href="psi_element://java.lang.CharSequence"><code>CharSequence</code></a></pre></div><div class='content'>
   The <code>String</code> class represents character strings. All
   string literals in Java programs, such as <code>"abc"</code>, are
   implemented as instances of this class.
   <p>
   Strings are constant; their values cannot be changed after they
   are created. String buffers support mutable strings.
   Because String objects are immutable they can be shared. For example:
   <p><blockquote><pre>
       String str = "abc";
   </pre></blockquote><p>
   is equivalent to:
   <p><blockquote><pre>
       char data[] = {'a', 'b', 'c'};
       String str = new String(data);
   </pre></blockquote><p>
   Here are some more examples of how strings can be used:
   <p><blockquote><pre>
       System.out.println("abc");
       String cde = "cde";
       System.out.println("abc" + cde);
       String c = "abc".substring(2,3);
       String d = cde.substring(1, 2);
   </pre></blockquote>
   <p>
   The class <code>String</code> includes methods for examining
   individual characters of the sequence, for comparing strings, for
   searching strings, for extracting substrings, and for creating a
   copy of a string with all characters translated to uppercase or to
   lowercase. Case mapping is based on the Unicode Standard version
   specified by the <a href="psi_element://java.lang.Character"><code>Character</code></a> class.
   <p>
   The Java language provides special support for the string
   concatenation operator (&nbsp;+&nbsp;), and for conversion of
   other objects to strings. String concatenation is implemented
   through the <code>StringBuilder</code>(or <code>StringBuffer</code>)
   class and its <code>append</code> method.
   String conversions are implemented through the method
   <code>toString</code>, defined by <code>Object</code> and
   inherited by all classes in Java. For additional information on
   string concatenation and conversion, see Gosling, Joy, and Steele,
   <i>The Java Language Specification</i>.
  
   <p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor
   or method in this class will cause a <a href="psi_element://java.lang.NullPointerException"><code>NullPointerException</code></a> to be
   thrown.
  
   <p>A <code>String</code> represents a string in the UTF-16 format
   in which <em>supplementary characters</em> are represented by <em>surrogate
   pairs</em> (see the section <a href="psi_element://java.lang.Character###unicode">Unicode
   Character Representations</a> in the <code>Character</code> class for
   more information).
   Index values refer to <code>char</code> code units, so a supplementary
   character uses two positions in a <code>String</code>.
   <p>The <code>String</code> class provides methods for dealing with
   Unicode code points (i.e., characters), in addition to those for
   dealing with Unicode code units (i.e., <code>char</code> values).
  
   </div><table class='sections'><p><tr><td valign='top' class='section'><p>Since:</td><td valign='top'><p>JDK1.0</td><tr><td valign='top' class='section'><p>See Also:</td><td valign='top'><p><a href="psi_element://java.lang.Object#toString()"><code>Object.toString()</code></a>,
<a href="psi_element://java.lang.StringBuffer"><code>StringBuffer</code></a>,
<a href="psi_element://java.lang.StringBuilder"><code>StringBuilder</code></a>,
<font color=red>java.nio.charset.Charset</font></td></table>